60/70 hour Recap calculator

Does anyone know of anything online that calculates your 60/70 hour log recap and hours available. I have seen calculators at truck stops but wondering if anyone has seen something online that does the same thing?

I can do it manually, but we don't have a 34hour restart so alot of times your running down to your last couple hours and its nice to be able to double check it so your not making any mistakes and actaully be over on hours. Just an easy way to double check my math.